Effective ways of tackling "us vs them" mentality?

Abhijeet, As per a research "US Vs Them" is one off the Top Ten Challenges of software testing. Its all about who gets the bigger share of credit and owns the responsibilities of not being traped. One thing I would stress on is to focus on integrating the testing team with the development team which is easily possible in an Agile model. Having an integrated test group to drive a fully functional and co-operative team that will have ownership of the things they do whether its testing or development.